The present invention relates to methods and compositions of stabilizing a surface within a subterranean formation or fracture. More particularly, the present invention relates to stabilizing surfaces within a subterranean formation or fracture using lightweight proppant coated with an adhesive substance.
Hydrocarbon-producing wells are often stimulated by hydraulic fracturing treatments. In hydraulic fracturing treatments, a viscous fracturing fluid, which also functions as a carrier fluid, is pumped into a producing zone at a rate and pressure such that one or more fractures are formed in the zone. Typically, particulates, such as graded sand, suspended in a portion of the fracturing fluid are then deposited in the fractures when the fracturing fluid is converted to a thin fluid to be returned to the surface. These particulate solids, or “proppant particulates,” serve to prevent the fractures from fully closing so that conductive channels are formed through which produced hydrocarbons can flow.
To prevent the subsequent flowback of proppant and other particulates with the produced fluids, a portion of the proppant introduced into the fractures may be coated with a curable resin or tackifying agent that may facilitate the consolidation of the proppant particles in the fracture. The partially closed fractures apply pressure to the coated proppant particulates whereby the particulates are forced into contact with each other while the resin or tackifying agent enhances the grain-to-grain contact between individual proppant particles. The action of the pressure and the resin or tackifying agent bring about the consolidation of the proppant particles into a permeable mass having compressive and tensile strength, while allowing small amounts of deformation at the surface of the proppant packs to reduce the effects of point loading and/or to reduce proppant crushing.
Most proppant pack treatments have focused on consolidating the proppant pack itself, neglecting the importance of the interaction between the mechanical properties of the subterranean formation in which the proppant pack is placed and the proppant pack. These interactions can have a dramatic effect on overall fracture conductivity. In particular, under high stress and/or high flow conditions, formation material can intrude into the proppant pack, potentially damaging the pack. The intrusion of formation material into the proppant pack can also increase the amount of point loading and/or proppant crushing experienced by the proppant pack. These phenomena can reduce the overall conductivity of the propped fracture and/or the permeability of the proppant pack, which may negatively affect the production of the well.